View full sizeA photo posted on his stepmother's Facebook page shows Kyron Horman in front of his science fair project, wearing the "CSI" T-shirt he was last seen in. Detectives will begin interviewing everyone who was at Skyline Elementary School when Kyron Horman disappeared as the search for the missing second-grader moves into its third day.

More than 100 searchers are expected to continue the hunt for the 7-year-old boy, while hundreds of adults and children will come to the pastoral school.

The 300 students and their parents, as well as teachers and support staff members, are expected to arrive in time-allotted slots to talk to detectives.

Law enforcement officials are searching for any clue to help them discover what happened to the boy, who was last seen Friday morning as he participated in a school science fair.

Through Saturday night, however, their effort -- with help from four county sheriff's departments, the Portland Police Bureau, the FBI and others -- had yielded nothing.

Sgt. David Thompson of the Washington County Sheriff's Office said officers remained hopeful that Kyron would be found safe and said that foul play was not suspected. The parents have been cooperative, and investigators were with them most of the day. But officials did not offer scenarios about how the child could have gone missing from the school, a vanishing that went undetected by teachers or any other adult.

It was unclear when the boy was reported absent. Robb Cowie, Portland Public Schools communications director, said school officials were asked by law enforcement not to comment on any details because it might impede the investigation. He said not all elementary schools use the automated call system that notifies parents when children are marked absent. He did not know whether Skyline used it.

Witnesses said Kyron arrived at the school with his stepmother, Terri Moulton Horman, on Friday morning, perhaps about 8 a.m. Parents had been invited to attend Skyline's annual schoolwide science fair, an event scheduled for 8 to 10 a.m., according to the PTA.

The stepmother said she last saw Kyron at about 8:45 a.m. walking down the hallway toward his classroom, according to a sheriff's office news release.

It was not clear, however, whether Kyron, like every other student in the school, then participated in a classroom-to-classroom inspection of other science projects.

Parent-led groups of about four students walked among the classrooms, said Gina Zimmerman, president of the Skyline PTA.

"You were supposed to stay with your group," Zimmerman said. "I don't know what group he was in."

However, the sheriff's office news release says school staff did not see Kyron after 8:45 a.m. and that he did not make it to his classroom.

Terri Horman called 9-1-1 about 3:45 p.m. Friday to report Kyron missing after he failed to return home at his usual time on the school bus.

Zimmerman could not believe Kyron would have just walked off the school grounds on his own.

"He's not the type of child who would just go out of school and go wandering around," said Zimmerman, whose 8-year-old daughter, Madi, is in Kyron's class and has known the boy for three years.

View full sizeCourtesy of Multnomah County Sheriff's DepartmentKyron Horman

"He's just a timid, sweet boy."

Portland police initially responded to the missing-person call, using search dogs throughout the school and also searching on the school roof, said Multnomah County sheriff's Capt. Jason Gates, the incident commander. The search was turned over later Friday to the sheriff's office, as the school is not within the city limits.

However, by Saturday, a vast range of police agencies and a National Guard helicopter took part in a search that went house to house, field by field spanning a two-mile radius around the school at 11536 N.W. Skyline Blvd.

"We want to throw everything we can at this," Gates said.

Throughout Saturday, concerned parents arrived at the school, some with their children in tow, offering to help.

Later Saturday, Gates said the offers were appreciated but interfered with the coordinated search. Pray for Kyron instead, he suggested, and call the tip hot line at 503-261-2847.

Also, he urged homeowners in the area -- bordered by modest homes and expansive fields on one side and hillside estates on the other -- to search their own property.

Gates would not comment on statements by a family member and others that Kyron's backpack and coat were found in his second-floor classroom.